Chronic heart failure (CHF) is a leading cause of morbidity and mortality. Exercise intolerance is a major limiting symptom in CHF and is due, in part to abnormalities of skeletal muscle. Reduced exercise capacity and degree of cachexia are associated with a poor prognosis. Anabolic steroids have increased lean body mass and improved muscle function in a number of wasting syndromes, but have not been studied in CHF. Specific Aims: To test the hypotheses that oxandrolone, an anabolic steroid with minimal androgenic effects, will: 1) increased skeletal muscles size and function and improve exercise capacity; 2) increase left ventricular (LV) mass and improve cardiac function in CHF patients. Methods: This will be a randomized, doubled-blind, placebo-controlled pilot study of 48 patients with ejection fractions (EF) <40% and impaired exercise tolerance. Eligible patients must have documented muscle wasting and reduced exercise capacity. At least 30% of the subjects will meet criteria for cardiac cachexia (non-intentional, non-edematous weight loss >7.5% of the previous weight over 6 months). Patients will be randomized to oxandrolone 10mg po bid or placebo in a 2:1 ratio. The following measurements will be made at baseline and after 4 months of treatment: 1) lean body mass by dual-energy-xray- absorptiometery; 2) strength and endurance of the quadriceps muscle by isokinetic dynamometry; 3) exercise capacity by respiratory gas exchange; 4) LV mass and EF by cardiac MRI.